RE: [PATCH v5 03/13] virtio-gpu: Add udmabuf helpers

["Kasireddy, Vivek" <vivek.kasireddy@intel.com>]

Hi Gerd,

> 
> > +#ifdef CONFIG_LINUX
> 
> > +void virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
> 
> > +#else
> 
> > +void *virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
> > +{
> > +    /* nothing (stub) */
> > +    return NULL
> > +}
> 
> Fails to build for !linux ...
> 
> You can place the stubs in a file in the stubs/ directory instead.
> They'll be used via weak symbol references instead of #ifdefs then.
> 
> Advantage: the stubs are compiled unconditionally so errors like this
> don't go unnoticed that easily.
[Kasireddy, Vivek] Gave it a try but because of res->image, we'd need to consider the
Pixman dependency. I think we have the following options to address this:
1) Add pixman dependency to stubs. This may not be acceptable given that the other
dependencies are glib, socket, etc which are pretty basic.
2) Cast the objects (such as virtio_gpu_simple_resource) as void * to the functions that
we have stubs for. This also may not be acceptable as I don't see other stubs doing this.
3) Move some core objects (such as VirtIOGPUBase and its dependencies that do not
deal with pixman) into a new header and include that in virtio-gpu.h and the new stubs
file. This seems like the way to go but needs some work as virtio-gpu.h has a lot of stuff
and is included in a lot of places. If it is not a problem, I can do this in a small separate
series but keep the ifdef for this series?

Will send out a v6 for this series soon.

Thanks,
Vivek

> 
> take care,
>   Gerd